1. Field of the Invention
The present invention relates to a map provision service, and more particularly, to a device for providing a tile map service (TMS) and a method of providing a TMS.
2. Discussion of Related Art
A web-based map service method has been developed in a variety of forms. A method of reconstructing map data having a vector form in a client (a user terminal) by transmitting the map data as it is and a method of generating a map having an image form in real time using map data of a server and displaying the map to a user by transmitting the map to a client are examples. Further, a tile map service (TMS) method has been developed as a method of storing map data in an image tile form in a server having a level of detail (LOD) structure and transmitting and showing only a tile map necessary according to a user's request to a client. The change of such map service methods has been focused on decreasing a user's standby time in consideration of limited client performance and network communication bandwidth.
Among the map service methods, in a TMS, map data of a server is configured as various kinds of layers such as A, B, . . . , and N shown in FIG. 1. Here, the various kinds of layers may be different types of layers such as a digital map, an aerial photograph map, an address map, and a geological map.
Further, map data of each layer is stored in an image tile form having an LOD structure such as LOD1, LOD2, . . . , and LODn shown in FIG. 1, a specific image tile map is transmitted, constructed, and visualized according to an LOD (or a zoom level) thereof and map coordinates requested by the user.
However, when the user wants to see plurality of layers instead of a single layer by combining data of the layers, it is necessary to merge tile maps of the layers. For this, in a current TMS, a method of providing a digital map layer, an aerial photograph layer, and a hybrid layer that is a result of previously merging the digital map layer and the aerial photograph layer has been used.
The current TMS method shows stable performance for a general purpose of providing a service based on a single layer, or a service based on a predetermined number of layers including a digital map, an aerial photograph map, and a hybrid map. However, in consideration of a recent trend in which types of data required to a map service have gradually been increased or more specialized applications have been used by experts rather than general users, a performance problem is occurring when dynamically merging and providing layers since the number of layers which are included in a map service has greatly increased. When a plurality of layers are added, and more particularly, when a layer to be added is not determined in advance, there is a problem in that merged layers have to be generated in advance.